以下是msdn中的例子！

[C#]
using System;
using System.Runtime.InteropServices;

public delegate bool CallBack(int hwnd, int lParam);

public class EnumReportApp {

    [DllImport("user32")]
    public static extern int EnumWindows(CallBack x, int y);

    public static void Main()
    {
        CallBack myCallBack = new CallBack(EnumReportApp.Report);
        EnumWindows(myCallBack, 0);
    }

   public static bool Report(int hwnd, int lParam) {
        Console.Write("Window handle is ");
        Console.WriteLine(hwnd);
        return true;
    }
}

我在自己的程序中是这样调用的

//定义委托

public unsafe delegate void CallBack(int hwnd, void* Param);

//引入Dll中的函数！
[DllImport("JPSystemApi.dll",EntryPoint="JPRegisterStreamReadCallback")]
  public unsafe static extern int JPRegisterStreamReadCallback(CallBack pCallBack,void* Context);

//实例化委托

CallBack F_myCallBack = new CallBack(JPRegister_StreamRead_Callback);

//注册委托
   int i = JPSystem._JPRegisterStreamReadCallback(F_myCallBack,n);
   GC.KeepAlive(F_myCallBack);//不回收

public unsafe static void JPRegister_StreamRead_Callback(int channel_number,void* point)
  {
   //this.richTextBox1.AppendText("start"+"\n");
   MessageBox.Show("显卡不支持！","Error",MessageBoxButtons.OK,MessageBoxIcon.Error);
  }

完全按照msdn中的过程来得！可是回调函数还是没有运行！不知道是什么原因？大家能给我个答复吗？